Method of preparing printing surfaces



March 7, 1944. 4 R MacKAY n 2,343,685

METHOD OF PREPARING PRINTING SURFACES Filed Apg. 9, 1941 Flaz.

23 INVEN TOR A706537 MAC KAV BY www,

ATTORNEY -by means of which the preparation Patented Mor. 7, 1944 UNITEDSTATES' Pai-Terriottici:

' ananas Ma'rnon orsrijtgtgo rmri'rmo Robert MacKay, Cook County, lll.,assigner i Alca-Gravure Division of Publication Corporation, New York,N'. Y., a corporation o! New York .The 'present invention relates toymetl'iods of preparing printing surfaces and embodies, more1 surfacesmay be facilitated.

More specifically, this vinvention embodies anl improved method by meansof which the size and location of art work may be readily andaccurately' established in the preparatory work prior to the etchingoperation. It is of particular utility in connection with the`preparation of printing surfaces which include aplurality of separateelements which must be located in a certain spaced relation on theprint. 'For example, where it is' necessary to include several pieces ciart work in a certain desired spaced relationship, the inventionprovides a method by means of which the several component parts of theprint formed by the several pieces of art work may be accuratelypositioned and formed of the proper size.

The present method is of particular utility in connection withmulti-color printing wherein separate printing elements must be made foreach ofthe colors forming component parts of theI print and is also ofspecial importance in connection with operations wherein inserts are tobe made Within the outline of a picture or other piece of art work.

Heretoiore the edges of pictures or other art work have been located andtrimmed by hand in ,the following manner. Assuming that a color page haslive separate pieces of color art to` be assembleciinto a given positionand that all ve pieces require cropping or trimming to t the various".positions designated for them on the print, separation negatives are setup in register from a master and positives are made. The edges of thepictures on one of these color positives are scraped by hand to fit theiinlshed layout and,.from'this positive. a photographic image is made onfilm. This film is positioned over each remaining positive and is usedasa guide in trimmingthe plates by hand. y l 4 l l There 'gare 4severalobjections to the foregoing operation, chief of which is that the handoperation is accomplished with a knife and ruler and is laborious andconstantly susceptible to the introduction 'of faults into the product.l A further objection residesin the fact that the iilm used as a guidein scraping' frequently changes size before the work is iinished on allof the plates.

In accordance with the present invention, an improved method is providedby means ofv which the trimming and positioning is accomplished of'printing photographically and with a high degree of ac- 5 curacy.speciiicaIIy, an improved 'photographic operationl f An object of thepresent invention, accordingly, is to provide an improved photographicmethod of preparing printing surfaces by means of which the location andsize of individual pieces of art work or component parts of the nalprint may be accurately maintained.

A further object of the invention is to provide a method of the above'character wherein the use of inserts within other -picture or similarareas may be greatly facilitated.

Further objects will be readily apparent as the invention is describedin greater detail and to illustrate the invention more fully, referencewill be made to the'accompanying drawing, wherein: Fig. l is anillustration of what will be called an originai to be reproduced,together with other' art work, in a print wherein all of the pieces ofart work are properly assembled.

Fig. 2 is a diagrammatic illustration of a layout composed offour piecesof art work, assembled in a desired relation, but in which the variouspieces are not of correct size.

Fig. 3 is a diagrammatic illustration of a burning or trimming plateutilized in connection with the method of the present invention.

Fig. 4 is an illustration of the art work of Fig. l, in the form of anal print which will be one of the elements of the composite print.

Referring to the drawing, it is assumed, in the illustration thereingiven, that the finished print is to consist of four pictures ill, ii,i2 and i3. These pictures are to be arranged in a desired spacedrelationship and to be of a predetermined exact size or sizes. Moreover,each of the pictures is assumed to be formed of a plurality l ofcomponent colors. Asillustrated in Fig.' l, the picture il includes adesign or ligure i4 and to illustrate the various uses to whichthefpresent invention can be put, it is to be assumed that cerfv` taindesiredlettersi 5 are to appear on the picture il above the figure i4.These letters may be white, that is-the color of the paper upon whichthe print is made, -or they may be formed-olfany.A

desired color. It is also assumed that the letter W is to appear in thelower portion of the iiguref` the picture I I.

edges to come as they will, so that the edges of all pictures on allplates extend beyond the size desired in the final print. The assembledpositive is then used tb make the carbon print which is to serve as theresist in the operation of etching the printing surface. Such a positiveis illustrated at Il in Fig. 2 and, to illustrate what has just beendescribed, the nal or desired edges of the various pictures areillustrated by dotted lines at I9.

In order that the final print may show the various pictures in theproper size and relationship, a wet plate negative is made from thecustomers layout which is usually drawn in ink and to accurate size.This negative is illustrated at 2l in Fig. 3 and is formed with theexact picture areas in black while all other areas are transparent sothat light may pass through The resulting negative is termed a burningor trimming plate because through it, the proper sizes of the picturesare obtained. After the exposure of the positive Il upon thecarbontissue, the trimming plate 20 is placed in register over the carbontissue and a second exposure made. This results in light, passingthrough the transparent areas of the burning plate and hardening thecarbon tissue under such areas so that no etching will take place on thecopper surface beneath such hardened areas. It will thus be apparentthat the edges of the pictures are trimmed photographically to the exactsize desired. The result is that all of the various color impressionswill occur in perfect register and sharply trimmed to the exact sizedesired.

To illustrate further'uses of the invention, it will be observed thatthe burning plate 20 is formed with letters I5 as transparent areas inthe desired position so that they will appear over the figureillustrated at I4, in Figs. 1 and 4. These transparent areas on theburning plate will cause the carbon tissue to be hardened and, as aresult, will prevent any etching beneath such areas. If no other coloris applied in these areas, the result will be that the picture II will-be fcrmed with the white letters I5 appearing sharply therein in thedesired position. If a dierent color is to be used for the letters I5,the desired color cylinder or plate will be etched in the areascorresponding to the letters I5 so that the final print will appear withthe letters i5 in the desired color.

It is further assumed that the letter W is to not be hardened under thisarea. The burning plate, within the area of the picture Il, isformedwith a transparent area 25 within which the design I1 is received, thedesign being opaque. As a result, the area 25 on the carbon tissue willbe hardened so that no etching will occur beneath it, whereas the areascorresponding to the design I1 will not be hardened and, accordingly,the design will be printed because of the desired etching accomplishedbeneath such area upon the exposure of the positive upon the carbontissue.

From the foregoing, it will be apparent that the invention dependsessentially upon the use of the `cus'tcimers layout as a means forprovidlike which are to be superimposed upon or inbe inserted within thefigure Il, appearing in This is accomplished .by blacking out thecorresponding area at 2| in the positive shown inv Fig. 2. As a result,the gelatin in the carbon tissue beneath the area. 21 will not behardened. The burning plate 20 is formed with a transparent area 22within which the letter W appears as opaque. Ihis is illustrated at Ilin Fig. 3. When the exposure is made through the burning plate, thetransparent area 22 causes the hardening of the unexposed area 2l sothat there will be no color applied in that area as illustrated at 2l inFig. 4. However, the opaque letter W in Fig. 3 prevents the hardening ofthe carbon tissue leluded within the picture areas and, while it hasbeen described with reference to Y the specific disclosure herein andillustrated in the drawing, it is not to be limited save as defined inthe appended claims.

I claim:

1 The method of preparing printing surfaces formed to reproduce desiredsubject matter in a desired size, comprising preparing a set oftransparent photographic color separation prints of the subject matter,preparing a layout of the print, forming a transparent photographicprint of the layout in which the area corresponding to the desiredsubject matter is opaque and of the correct size, exposing each colorseparation print on a separate carbon tissue and exposing saidphotographic print of the layout in succession on said carbon tissueswhereby the photographic print of the layout will trim the area of thesubject matter to the desired size, and preparing a printing surfacetherefrom in a known fashion.

2. The method of preparing printing surfaces formed to reproduce aplurality of desired subjects in desired sizes and space relationshipscomprising preparing a set of transparent composite photographic colorseparation positives containing the subjects infapproximately correctsizes and space relationship, preparing a layout of the finished print,preparing a photographic print of the layout in which the areascorresponding to the desired subjects are opaque and of correct size andthe remaining area is transparent, exposing each positive on a separatecarbon tissue and exposing said photographic print on said carbontissues whereby the photographic print will trim the areas of thesubjects to 'the desired sizes, and preparing a printing surfacetherefrom in a known fashion. j

3. The method of preparing printing surfaces formed to reproduce desiredsubject matter in a desired size and with other subject matter insertedtherein, comprising preparing a set of photographic color separationtransparencies of the desired subject matter, preparing a layout of theprint with the inserted subject matter thereon in the desired position,forming a photographic print of the layout in which the areacorresponding to said desiredsubject matter is in the form of atransparency of said inserted subject matter, exposing the colorseparation transparencies on separate carbon tissues and exposing saidphotographic print on at least one of said assesses area correspondingto said desired subject matter is opaque except in the areascorresponding to i5 the location of said inserted subject matter and ofthe correct size and said inserted subject matter is in the form of apositive print, opaquing out areas in said color separation positivesthat are 'to receive said inserted subject matter, exposing thepositives on separate carbon tissues, and reexposing said carbon tissuesthrough said photographie print whereby the photographic print will trimthe area of the subject matter to Ithe desired size, and said insertedsubject matter will be exposed in the desired areas of said desiredsubject matter and preparing a printing surface therefrom in a knownfashion.

ROBERT MACKAY.

